Semiconductor light emitting device

ABSTRACT

The embodiment discloses a semiconductor light emitting device. The semiconductor light emitting device includes a first conductive semiconductor layer; a first electrode layer below the first conductive semiconductor layer; a semiconductor layer at an outer peripheral portion of the first conductive semiconductor layer; an active layer on the first conductive semiconductor layer; a second conductive semiconductor layer on the active layer; and a second electrode layer on the second conductive semiconductor layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit under 35 U.S.C. §119 ofKorean Patent Application No. 10-2009-0012482, filed Feb. 16, 2009,which is hereby incorporated by reference in its entirety.

BACKGROUND

The embodiment relates to a semiconductor light emitting device and amethod of manufacturing the same.

Groups III-V nitride semiconductors have been extensively used as mainmaterials for light emitting devices, such as a light emitting diode(LED) or a laser diode (LD), due to the physical and chemicalcharacteristics thereof. In general, the groups III-V nitridesemiconductors include a semiconductor material having a compositionalformula of In_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1, and 0≦x+y≦1).

The LED is a semiconductor device, which transmits signals by convertingan electric signal into infrared ray or light using the characteristicsof compound semiconductors. The LED is also used as a light source.

The LED or LD using the nitride semiconductor material is mainly usedfor the light emitting device to provide the light. For instance, theLED or the LD is used as a light source for various products, such as akeypad light emitting part of a cellular phone, an electric signboard,and an illumination device.

SUMMARY

The embodiment provides a semiconductor light emitting device and amethod of manufacturing the same, capable of reducing currentconcentration onto an edge area of a first conductive semiconductorlayer.

The embodiment provides a semiconductor light emitting device and amethod of manufacturing the same, capable of reducing currenttransferred to an edge area of a first conductive semiconductor layer byforming a semiconductor layer having relatively low-concentration at anouter peripheral portion of the first conductive semiconductor layer.

According to an embodiment of the present invention, there is provided asemiconductor light emitting device comprising: a first conductivesemiconductor layer; a first electrode layer below the first conductivesemiconductor layer; a semiconductor layer at an outer peripheralportion of the first conductive semiconductor layer; an active layer onthe first conductive semiconductor layer; a second conductivesemiconductor layer on the active layer; and a second electrode layer onthe second conductive semiconductor layer.

According to another embodiment of the present invention, there isprovided a semiconductor light emitting device comprising: a firstconductive semiconductor layer including a first electrode contact layerand a first conductive nitride layer on the first electrode contactlayer; a first electrode layer below the first conductive semiconductorlayer; a semiconductor layer at a lateral side of the first electrodecontact layer and at an outer lower portion of the first conductivenitride layer; an active layer on the first conductive nitride layer; asecond conductive semiconductor layer on the active layer; and a secondelectrode layer on the second conductive semiconductor layer.

According to still another embodiment of the present invention, there isprovided a method of manufacturing a semiconductor light emittingdevice, the method comprising forming a first semiconductor layer on asubstrate; forming a semiconductor layer on an outer peripheral portionof the first conductive semiconductor layer; forming an active layer onthe first conductive semiconductor layer; forming a second conductivesemiconductor layer on the active layer; and forming a second electrodelayer on the second conductive semiconductor layer.

The embodiment can prevent current applied to a first electrode layerfrom being concentrated onto an edge area.

The embodiment can improve light emitting efficiency.

The embodiment can improve reliability of the semiconductor lightemitting device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a semiconductor light emitting deviceaccording to an embodiment;

FIG. 2 is a bottom view of a semiconductor light emitting deviceaccording to an embodiment; and

FIGS. 3 to 14 are sectional views showing the procedure formanufacturing a semiconductor light emitting device according to anembodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the description of the embodiments, it will be understood that, whena layer (or film), a area, a pattern, or a structure is referred to asbeing “on” or “under” another substrate, another layer (or film),another area, another pad, or another pattern, it can be “directly” or“indirectly” on the other substrate, layer (or film), area, pad, orpattern, or one or more intervening layers may also be present. Such aposition of the layer has been described with reference to the drawings.

The thickness and size of each layer shown in the drawings can beexaggerated, omitted or schematically drawn for the purpose ofconvenience or clarity. In addition, the size of elements does notutterly reflect an actual size.

Hereinafter, the embodiments will be described with reference to theaccompanying drawings.

FIG. 1 is a sectional view showing a semiconductor light emitting deviceaccording to an embodiment, and FIG. 2 is a bottom view of asemiconductor light emitting device according to an embodiment.

Referring to FIGS. 1 and 2, the semiconductor light emitting device 100according to the embodiment includes a light emitting structure 110, asemiconductor layer 120, a channel layer 130, a second electrode layer140 and a conductive support member 150.

The light emitting structure 110 includes a first conductivesemiconductor layer 111 having a first electrode contact layer 111A anda first conductive nitride layer 111B, an active layer 113, and a secondconductive semiconductor layer 115. The active layer 113 is interposedbetween the first and second conductive semiconductor layers 111 and115.

The first conductive semiconductor layer 111 may include both firstelectrode contact layer 111A and first conductive nitride layer 111B, orthe first conductive nitride layer 111B may be omitted.

The first electrode contact layer 111A may include at least onesemiconductor layer doped with a first conductive dopant. The firstelectrode contact layer 111A may include a group III-V compoundsemiconductor. For instance, the first electrode contact layer 111A mayinclude at least one selected from the group consisting of GaN, InN,AlN, InGaN, AlGaN, InAlGaN and AlInN. If the first electrode contactlayer 111A is an N type semiconductor layer, the first conductive dopantis an N type dopant. For instance, the N type dopant can be selectedfrom the group consisting of Si, Ge, Sn, Se and Te.

A first electrode layer 119 having a predetermined pattern can bedisposed under the first electrode contact layer 111A. The firstelectrode layer 119 may have a circular pattern, a polygonal pattern ora pattern having a branch structure. A roughness having concave-convexconfiguration can be formed on a part or a whole area of the bottomsurface of the first electrode contact layer 111A.

The first conductive nitride layer 111B is formed on the first electrodecontact layer 111A. The first conductive nitride layer 111B may includeat least one semiconductor layer doped with a first conductive dopant.The first conductive nitride layer 111B may include a group III-Vcompound semiconductor. For instance, the first conductive nitride layer111B may include at least one selected from the group consisting of GaN,InN, AlN, InGaN, AlGaN, InAlGaN and AlInN. If the first conductivenitride layer 111B is an N type semiconductor layer, the firstconductive dopant is an N type dopant. For instance, the N type dopantcan be selected from the group consisting of Si, Ge, Sn, Se and Te.

The semiconductor layer 120 is formed at an outer peripheral portion ofthe first electrode contact layer 111A. The semiconductor layer 120 maybe a lightly doped semiconductor layer or an undoped semiconductorlayer. The semiconductor layer 120 may include at least one selectedfrom the group consisting of GaN, InN, AlN, InGaN, AlGaN, InAlGaN andAlInN. The semiconductor layer 120 is disposed at a lateral side of thefirst electrode contact layer 111A and an outer lower portion of thefirst conductive nitride layer 111B.

The thickness T of the semiconductor layer 120 may be less than thethickness of the first electrode contact layer 111A. In addition, thethickness T of the semiconductor layer 120 may be equal to or greaterthan the thickness of the first electrode contact layer 111A. Thesemiconductor layer 120 may have the thickness reaching the upperportion of the first conductive nitride layer 111B. Further, the firstelectrode contact layer 111A is spaced apart from the active layer 113by a predetermined distance.

The first electrode contact layer 111A and the first conductive nitridelayer 111B may have carrier concentration higher than that of thesemiconductor layer 120. That is, the semiconductor layer 120 has acarrier concentration lower than a carrier concentration of the firstconductive semiconductor layer 111. For instance, the carrierconcentration of the first electrode contact layer 111A and the firstconductive nitride layer 111B is 5˜9×10¹⁸ cm⁻³ or above. The carrierconcentration of the semiconductor layer 120 is lower than the carrierconcentration of the first electrode contact layer 111A and the firstconductive nitride layer 111B. For instance, the carrier concentrationof the semiconductor layer 120 is 1˜5×10¹⁵ cm⁻³ or below.

In addition, the semiconductor layer 120 may be doped with a firstconductive dopant at low concentration. The semiconductor layer 120 canbe additionally doped with a second conductive dopant or thesemiconductor layer 120 may not be doped with the conductive dopant.

The active layer is formed on the first conductive nitride layer 111B.The active layer 113 has a single quantum well structure or a multiplequantum well (MQW) structure. The active layer 113 may have a stackstructure including a well layer and a barrier layer, which are madefrom group III-V compound semiconductor material. For instance, theactive layer 113 has a stack structure of InGaN well/GaN barrier layersor AlGaN well/GaN barrier layers.

The active layer 113 is made from material having band gap energyaccording to wavelength of light to be emitted. For instance, in thecase of blue light having wavelength of 460 to 470 nm, the active layer113 has a single quantum well structure or a multiple quantum wellstructure including the InGaN well/GaN barrier layers. The active layer113 may include material capable of providing light of visible ray band,such as blue light, red light and green light.

A conductive clad layer may be formed on and/or under the active layer.The conductive clad layer may include an AlGaN layer.

The second conductive semiconductor layer 115 is disposed on the activelayer 113. The second conductive semiconductor layer 115 includes atleast one semiconductor layer doped with the second conductive dopant.The second conductive semiconductor layer 115 may include a group III-Vcompound semiconductor. For instance, the second conductive layer 115may include at least one selected from the group consisting of GaN, InN,AlN, InGaN, AlGaN, InAlGaN and AlInN. If the second conductivesemiconductor layer is a P type semiconductor layer, the secondconductive dopant is a P type dopant. For instance, the P type dopantcan be selected from the group consisting of Mg, Zn, Ca, Sr and Ba.

A third conductive semiconductor layer (not shown) is formed on thesecond conductive semiconductor layer 115. If the first conductivesemiconductor layer 111 is a P type semiconductor layer, the secondconductive semiconductor layer 115 is an N type semiconductor layer. Thethird conductive semiconductor layer may be doped with the firstconductive dopant. The light emitting structure 110 may include one ofan N-P junction structure, a P-N junction structure, an N-P-N junctionstructure, and a P-N-P junction structure.

The channel layer 130 and the second electrode 140 are aligned on thesecond conductive semiconductor layer 115.

An inner portion of the channel layer 130 is disposed on the secondconductive semiconductor layer 115 along an outer peripheral portion ofthe second conductive semiconductor layer 115. An outer portion of thechannel layer 130 extends out of the second conductive semiconductorlayer 115 so that the outer portion of the channel layer 130 is exposedat an outer area A1 of the light emitting structure 110. The channellayer 130 may be formed on a boundary area of the top of the secondelectrode layer 140. That is, the channel layer 130 may be formed on theboundary area between the light emitting structure 110 and the secondelectrode layer 140. The channel layer 130 may be disposed between anouter upper portion of the second conductive semiconductor layer 115 andthe second electrode layer 140. The channel layer 130 may be formed of aconductive channel layer using a conductive material or a non-conductivechannel layer using a non-conductive material.

The conductive channel layer may be formed of a transparent conductiveoxide layer or may include at least one of Ti, Ni, Pt, Pd, Rh, Ir, andW. For example, the transparent conductive oxide layer may be formed ofat least one of indium tin oxide (ITO), indium zinc oxide (IZO), indiumzinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium galliumzinc oxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide(AZO), antimony tin oxide (ATO), and gallium zinc oxide (GZO).

In addition, if isolation etching is performed on the light emittingstructure 110 to separate the light emitting structure 110 by a unitchip without the channel layer 121 during a chip separation process,fragments are generated from the second electrode layer 130. Thefragments are attached between the second conductive semiconductor layer115 and the active layer 113 or between the active layer 113 and thefirst conductive semiconductor layer 111, such that electrical short mayoccur. Accordingly, the conductive protective layer is formed of amaterial that is not cracked or does not generate fragments duringisolation etching. Therefore, the fragments of the second electrodelayer 130 are not generated and the electrical short is not occurred.

In other words, the channel layer 130 may include conductive material orinsulating material having light transmittive property. The channellayer 130 is prepared in the form of a frame and is disposed between anouter portion of the second conductive semiconductor layer 115 and thesecond electrode layer 140.

The channel layer 130 may include insulating material selected from thegroup consisting of ZnO, SiO₂, SiO_(x), SiO_(x)N_(y), Si₃N₄, Al₂O₃ andTiO₂. When the channel layer 130 includes the insulating material, thegap between the second electrode layer 140 and the light emittingstructure 110 can be widened.

The channel layer 130 may partially overlap the light emitting structure110 in a vertical direction. The channel layer 130 may partially overlapthe semiconductor layer 120 in a vertical direction.

The channel layer 130 increases the distance of the side between thesecond electrode layer 140 and the active layer 113. Accordingly,probability that electrical short occurs between the second electrodelayer 140 and the active layer 113 can be reduced.

A partial top of the channel layer 130 may be exposed by the isolationetching. Accordingly, the channel layer 130 may contact a partial areaof the light emitting structure 110 in a vertical direction and theremaining portion may not contact the light emitting structure 110 in avertical direction.

The second electrode layer 140 is formed on the second conductivesemiconductor layer 115 and the channel layer 130. The second electrodelayer 140 includes at least one layer including at least one selectedfrom the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au,Hf and combination thereof.

An ohmic layer (not shown) having a predetermined pattern can be formedbetween the second electrode layer 140 and the second conductivesemiconductor layer 115. The ohmic layer may have a matrix pattern, across pattern, a polygonal pattern or a circular pattern. The ohmiclayer may include at least one selected from the group consisting of ITO(indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tinoxide), IAZO (indium aluminum zinc oxide), IGZO (indium gallium zincoxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide) andATO (antimony tin oxide). The light emitting structure 110 may be formedon the ohmic contact layer and the channel layer 130.

The conductive support member 150 is formed on the second electrodelayer 140. That is, the conductive support member 150 may be disposed onthe second electrode layer 140. The conductive support member 150 mayinclude material selected from the group consisting of copper, gold, andcarrier wafers (for instance, Si, Ge, GaAs, ZnO, and SiC).

FIGS. 3 to 14 are sectional views showing the procedure formanufacturing the semiconductor light emitting device according to theembodiment.

Referring to FIG. 3, a buffer layer 103 is formed on a substrate 101,and the first electrode contact layer 111A is formed on the buffer layer103.

The substrate 101 may include material selected from the groupconsisting of Al₂O₃, GaN, SiC, ZnO, Si, GaP, InP or GaAs. Apredetermined concave-convex pattern can be formed on the substrate 101.

A nitride semiconductor can be grown on the substrate 101. In this case,growth equipment may be selected from the group consisting of E-beamevaporator, PVD (physical vapor deposition), CVD (chemical vapordeposition), PLD (plasma laser deposition), dual-type thermalevaporator, sputtering, and MOCVD (metal organic chemical vapordeposition). However, the embodiment is not limited to the above growthequipment. For instance, the nitride semiconductor may include acompound semiconductor having a chemical formula ofIn_(x)Al_(y)Ga_(1-x-y)N (0≦x≦1, 0≦y≦1, and 0≦x+y≦1).

The buffer layer 103 is formed on the substrate 101. The buffer layer103 attenuates the lattice mismatch between the semiconductor layer tobe grown on the buffer layer 103 and the substrate 101. For instance,the buffer layer 103 attenuates the lattice mismatch between the GnNlayer to be grown on the buffer layer 103 and the substrate 101. Thebuffer layer may include at least one selected from the group consistingof GaN, InN, AlN, InGaN, AlGaN, InAlGaN and AlInN. An undopedsemiconductor layer (not shown) or another semiconductor layer can beformed on the buffer layer 103. The undoped semiconductor layer mayinclude an undoped GaN layer, which is not doped with the first orsecond conductive dopant. The buffer layer 103 and/or the undopedsemiconductor layer may be omitted or may not exist in the resulteddevice.

The first electrode contact layer 111A includes at least onesemiconductor layer doped with the first conductive dopant. The firstelectrode contact layer 111A may include a group III-V compoundsemiconductor. For instance, the first electrode contact layer 111A mayinclude at least one selected from the group consisting of GaN, InN,AlN, InGaN, AlGaN, InAlGaN and AlInN. If the first electrode contactlayer 111A is an N type semiconductor layer, the first conductive dopantis an N type dopant. For instance, the N type dopant can be selectedfrom the group consisting of Si, Ge, Sn, Se and Te.

If the first electrode contact layer 111A is an N—GaN layer, the N typedopant, silane gas including the N type dopant, such as NH₃, TMGa (orTEGa) or Si, is supplied to form the N type GaN layer having apredetermined thickness.

Referring to FIGS. 4 to 6, a recess 105 is formed in the first electrodecontact layer 111A to form the semiconductor layer 120. The recess 105can be formed by etching a chip boundary area through a dry etchingusing a mask pattern. A depth of the recess 105 is equal to or more thanthe thickness of the first electrode contact layer 111A, but theembodiment is not limited thereto. The recess 105 can be prepared in theform of a strip along the chip boundary area.

The semiconductor layer 120 is formed in the recess 105 of the firstelectrode contact layer 111A. The semiconductor layer 120 may be alightly doped semiconductor layer or an undoped semiconductor layer. Thesemiconductor layer 120 may include at least one selected from the groupconsisting of GaN, InN, AlN, InGaN, AlGaN, InAlGaN and AlInN. If thesemiconductor layer 120 is an undoped GaN layer, the semiconductor layer120 can be formed by supplying NH₃ or TMGa (or TEGa).

The semiconductor layer 120 has carrier concentration lower than that ofthe first electrode contact layer 111A. If the first electrode contactlayer 111A has normal carrier concentration, the semiconductor layer 120has low carrier concentration or the semiconductor layer 120 is undoped.In addition, if the first electrode contact layer 111A has high carrierconcentration, the semiconductor layer 120 has low carrier concentrationor the semiconductor layer 120 is undoped.

For instance, the carrier concentration of the first electrode contactlayer 111A is 5˜9×10¹⁸ cm⁻³ or above. The carrier concentration of thesemiconductor layer 120 is lower than the carrier concentration of thefirst electrode contact layer 111A. For instance, the carrierconcentration of the semiconductor layer 120 is 1˜5×10¹⁵ cm⁻³ or below.

That is, the semiconductor layer 120 is doped with the first conductivedopant at low concentration or doped with the second conductive dopant.In addition, the semiconductor layer 120 may not be doped with theconductive dopant.

Referring to FIGS. 5 to 7, the first conductive nitride layer 111B isformed on the first electrode contact layer 111A and the semiconductorlayer 120. The first conductive nitride layer 111B may include at leastone semiconductor layer doped with the first conductive dopant. Thefirst conductive nitride layer 111B may include a group III-V compoundsemiconductor. For instance, the first conductive nitride layer 111B mayinclude at least one selected from the group consisting of GaN, InN,AlN, InGaN, AlGaN, InAlGaN and AlInN. If the first conductive nitridelayer 111B is an N type semiconductor layer, the first conductive dopantis an N type dopant. For instance, the N type dopant can be selectedfrom the group consisting of Si, Ge, Sn, Se and Te.

The first conductive nitride layer 111B may include the semiconductormaterial identical to or different from the first electrode contactlayer 111A and the embodiment is not limited thereto. The carrierconcentration of the first conductive nitride layer 111B is higher thanthat of the semiconductor layer 120. For instance, the first conductivenitride layer 111B has the carrier concentration of 5˜9×10¹⁸ cm⁻³ orabove.

The first conductive nitride layer 111B may be omitted. In this case,the first electrode contact layer 111A has relatively large thicknessand the semiconductor layer 120 has thickness corresponding to ½˜⅗thickness of the first electrode contact layer 111A. In addition, thetop surface of the semiconductor layer 120 may be sealed by the nitridesemiconductor layer (for instance, the first conductive semiconductorlayer).

Referring to FIG. 8, the active layer 113 is formed on the firstconductive nitride layer 111B of the first conductive semiconductorlayer 111, and the second conductive semiconductor layer 115 is formedon the active layer 113.

The active layer 113 has a single quantum well structure or a multiplequantum well (MQW) structure. The active layer 113 may have a stackstructure including a well layer and a barrier layer, which are madefrom group III-V compound semiconductor material. For instance, theactive layer 113 has a stack structure of InGaN well/GaN barrier layersor AlGaN well/GaN barrier layers.

A conductive clad layer may be formed on and/or under the active layer.The conductive clad layer may include an AlGaN layer.

The second conductive semiconductor layer 115 includes at least onesemiconductor layer doped with the second conductive dopant. The secondconductive semiconductor layer 115 may include a group III-V compoundsemiconductor. For instance, the second conductive layer 115 may includeat least one selected from the group consisting of GaN, InN, AlN, InGaN,AlGaN, InAlGaN and AlInN. If the second conductive semiconductor layer115 is a P type semiconductor layer, the second conductive dopant is a Ptype dopant. For instance, the P type dopant can be selected from thegroup consisting of Mg, Zn, Ca, Sr and Ba.

A third conductive semiconductor layer (not shown) is formed on thesecond conductive semiconductor layer 115. If the first conductivesemiconductor layer 111 is a P type semiconductor layer, the secondconductive semiconductor layer 115 is an N type semiconductor layer. Thethird conductive semiconductor layer may be doped with the firstconductive dopant. The light emitting structure 110 may include one ofan N-P junction structure, a P-N junction structure, an N-P-N junctionstructure, and a P-N-P junction structure.

Referring to FIG. 9, the channel layer 130 is formed on the top surfaceof the second conductive semiconductor layer 115. The channel layer 130may include one selected from the group consisting of ITO, IZO, IZTO,IAZO, IGZO, IGTO, AZO, ATO, SiO₂, SiO_(x), SiO_(x)N_(y), Si₃N₄, Al₂O₃and TiO₂.

The channel layer 130 is prepared in the form of a frame at an edge areaof the second conductive semiconductor layer 115 of the chip. Thechannel layer may include light transmittive material or insulatingmaterial.

In other words, the channel layer 130 may be selectively formed on thelight emitting structure 110, being corresponding to a unit chip area.

The channel layer 130 may be formed on a boundary of the unit chip areausing a mask pattern. The channel layer 130 may be formed using variousdeposition methods such as a sputtering method.

Referring to FIGS. 9 and 10, the second electrode layer 140 is formed onthe channel layer 130 and the second conductive semiconductor layer 115,and the conductive support member 150 is formed on the second electrodelayer 140.

The second electrode layer 140 and the conductive support member 150 areconductive layers that serve as a second electrode. An ohmic pattern(not shown) having a predetermined pattern can be formed between thesecond conductive semiconductor layer 115 and the second electrode layer140.

The second electrode layer 140 may include at least one layer includingat least one selected from the group consisting of Ag, Ni, Al, Rh, Pd,Ir, Ru, Mg, Zn, Pt, Au, Hf and combination thereof, but the embodimentis not limited thereto. The conductive support member 150 may includematerial selected from the group consisting of copper, gold, and carrierwafers (for instance, Si, Ge, GaAs, ZnO, and SiC), but the embodiment isnot limited thereto.

Referring to FIGS. 10 and 11, the substrate 101 disposed below the firstelectrode contact layer 111A is removed. For instance, the substrate 101can be removed through the laser lift off (LLO) scheme. That is, if thelaser having a predetermined wavelength band is irradiated onto thesubstrate 101, thermal energy is concentrated on the boundary surfacebetween the substrate 101 and the first electrode contact layer 111A, sothat the substrate 101 is separated from the first electrode contactlayer 111A. After removing the substrate 101, the buffer layer 103 isremoved through an etching scheme.

The substrate 101 can be removed through another scheme. For instance,if the buffer layer 103 exists between the substrate 101 and the firstconductive semiconductor layer 111, wet etchant is injected into thebuffer layer 103 to remove the buffer layer 103, thereby removing thesubstrate 101.

After the substrate 101 has been removed, the bottom surface of thefirst electrode contact layer 111A polished through the ICP/RIE(inductively coupled plasma/reactive ion etching) scheme.

Referring to FIGS. 12 and 13, after the substrate 101 has been removed,a mesa etching is performed to expose an outer lower portion of thechannel layer 130 at the chip boundary area. The mesa etching may be thedry etching or the wet etching. At this time, the outer area A1 of thelight emitting structure 110 is cut.

If the channel layer 130 includes conductive material, the lightemitting efficiency can be improved due to the ohmic characteristic ofthe channel layer 130. If the channel layer 130 includes insulatingmaterial, the gap between the second electrode 140 and the secondconductive semiconductor layer 114 can be widened.

The first electrode layer 119 having a predetermined pattern can beformed below the first electrode contact layer 111A. The concave-convexroughness can be formed on the bottom surface of the first electrodecontact layer 111A. After or before the first electrode layer 119 hasbeen formed, a dicing process is performed to provide individual chips.

If forward power is supplied to the semiconductor light emitting device100, power is applied to the first electrode layer 119 and theconductive support member 150. The first electrode contact layer 111A ofthe light emitting structure 110 is formed at an outer peripheralportion thereof with the semiconductor substrate 120. Thus, current maynot flow to an edge (that is, an outer peripheral portion) of the firstelectrode contact layer 111A, but flow to the active layer 120 throughthe first conductive nitride layer 111B. The semiconductor lightemitting device according to the embodiment can minimize the currentflowing through the edge of the device, so that the light emittingefficiency and reliability of the device can be improved.

The semiconductor light emitting device according to the embodiments canbe applied to various devices, such as a light emitting device package,a backlight unit, and an illumination device.

The light emitting device package may include a body, a first leadelectrode, a second lead electrode, a semiconductor light emittingdevice according to the embodiments, and a molding member.

The first lead electrode and the second lead electrode may be disposedat the body. The semiconductor light-emitting device may be electricallyconnected to the first lead electrode and the second lead electrode. Themolding member may be configured to mold the semiconductor lightemitting device.

The body may be formed to include, for example, silicon material,synthetic resin, or metallic material, and an inclined surface may beformed around the semiconductor light emitting device. The first leadelectrode and the second lead electrode may be electrically disconnectedfrom each other, and may provide power to the semiconductor lightemitting device. Also, the first lead electrode and the second leadelectrode may reflect light emitted from the semiconductor lightemitting device, thus increasing light efficiency. Also, the first leadelectrode and the second lead electrode may serve to discharge heatgenerated by the semiconductor light emitting device.

The semiconductor light emitting device may be disposed on the body, ormay be disposed on the first lead electrode or the second leadelectrode. The semiconductor light emitting device may be electricallyconnected by, for example, a wire to the first lead electrode, and maybe connected to the second lead electrode in, for example, a die-bondingconfiguration.

The molding member may mold the semiconductor light emitting device toprotect the semiconductor light emitting device. Also, a fluorescentmaterial may be included in the molding member to change a wavelength oflight emitted from the semiconductor light emitting device.

The semiconductor light emitting device according to embodiments may bepackaged in, for example, a semiconductor substrate, an insulatingsubstrate, or a ceramic substrate (such as resin material or silicon).

The semiconductor light emitting device according to the embodiments canbe applied to a backlight unit.

The backlight unit can be adapted to a display apparatus such as aliquid crystal display to supply light to the display apparatus. Thebacklight unit may include a light supply part, a light guide plate, andan optical sheet. The light emitting device package according to theembodiment can be adapted to the light supply part. The backlight unitmay not employ the light guide plate.

The semiconductor light emitting device according to the embodiments canbe applied to an illumination device.

The illumination device may include a case and a light supply module.The light supply module may be disposed in the case. The light emittingdevice package according to the embodiments can be adapted to the lightsupply module.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

1. A semiconductor light emitting device, comprising: a first conductive semiconductor layer; a first electrode layer below the first conductive semiconductor layer; a semiconductor layer at an outer peripheral portion of the first conductive semiconductor layer; an active layer on the first conductive semiconductor layer; a second conductive semiconductor layer on the active layer; and a second electrode layer on the second conductive semiconductor layer, wherein a portion of the semiconductor layer is disposed under a portion of the first conductive semiconductor layer and the semiconductor layer has a carrier concentration lower than a carrier concentration of the first conductive semiconductor layer.
 2. The semiconductor light emitting device according to claim 1, wherein the semiconductor layer is not vertically overlapped with the first electrode layer.
 3. The semiconductor light emitting device according to claim 1, wherein the semiconductor layer includes an undoped semiconductor layer.
 4. The semiconductor light emitting device according to claim 1, wherein the semiconductor layer is spaced apart from the active layer.
 5. The semiconductor light emitting device according to claim 1, wherein the first conductive semiconductor layer includes a first electrode contact layer and a first conductive nitride layer.
 6. The semiconductor light emitting device according to claim 5, wherein the first electrode contact layer is disposed on the first electrode layer and at a lateral side of the semiconductor layer.
 7. The semiconductor light emitting device according to claim 5, wherein the first conductive nitride layer has a carrier concentration higher than a carrier concentration of the semiconductor layer.
 8. The semiconductor light emitting device according to claim 5, wherein the first electrode contact layer and the first conductive nitride layer have a carrier concentration of about 5˜9×10¹⁸ cm⁻³ or above.
 9. The semiconductor light emitting device according to claim 5, wherein the semiconductor layer is disposed at a lateral side of the first electrode contact layer and at an outer lower portion of the first conductive nitride layer.
 10. The semiconductor light emitting device according to claim 1, further comprising a channel layer disposed between an outer upper portion of the second conductive semiconductor layer and the second electrode layer.
 11. The semiconductor light emitting device according to claim 10, wherein the channel layer is formed of conductive material or insulating material.
 12. The semiconductor light emitting device according to claim 1, further comprising a conductive support member disposed on the second electrode layer.
 13. The semiconductor light emitting device according to claim 1, wherein the semiconductor layer has a carrier concentration of about 1˜5×10¹⁵ cm⁻³ or below.
 14. The semiconductor light emitting device according to claim 1, wherein the semiconductor layer includes at least one selected from the group consisting of GaN, InN, AlN, InGaN, AlGaN, InAlGaN and AlInN.
 15. The semiconductor light emitting device according to claim 1, wherein the semiconductor layer is doped with at least one material selected from the group consisting of Si, Ge, Sn, Se and Te.
 16. A semiconductor light emitting device, comprising: a first conductive semiconductor layer including a first electrode contact layer and a first conductive nitride layer on the first electrode contact layer; a first electrode layer below the first conductive semiconductor layer; a semiconductor layer at a lateral side of the first electrode contact layer and at an outer lower portion of the first conductive nitride layer; an active layer on the first conductive nitride layer; a second conductive semiconductor layer on the active layer; and a second electrode layer on the second conductive semiconductor layer, wherein a portion of the semiconductor layer is disposed under a portion of the first conductive semiconductor layer and the semiconductor layer has a carrier concentration lower than a carrier concentration of the first conductive nitride layer.
 17. The semiconductor light emitting device according to claim 16, wherein the semiconductor layer is not vertically overlapped with the first electrode layer.
 18. The semiconductor light emitting device according to claim 16, wherein the first electrode contact layer and the first conductive nitride layer have a carrier concentration of about 5˜9×10¹⁸ cm⁻³ or above.
 19. The semiconductor light emitting device according to claim 16, wherein the semiconductor layer has a carrier concentration of about 1˜5×10¹⁵ cm⁻³ or below.
 20. The semiconductor light emitting device according to claim 16, wherein the semiconductor layer is doped with at least one material selected from the group consisting of Si, Ge, Sn, Se and Te. 